diff --git a/packages/flutter/lib/src/animation/scheduler.dart b/packages/flutter/lib/src/animation/scheduler.dart
index 2d374f83575..8b1d891b465 100644
--- a/packages/flutter/lib/src/animation/scheduler.dart
+++ b/packages/flutter/lib/src/animation/scheduler.dart
@@ -31,7 +31,6 @@ class Scheduler {
   }
 
   bool _haveScheduledVisualUpdate = false;
-  int _nextPrivateCallbackId = 0; // negative
   int _nextCallbackId = 0; // positive
 
   final List<SchedulerCallback> _persistentCallbacks = new List<SchedulerCallback>();
@@ -55,7 +54,6 @@ class Scheduler {
     Duration timeStamp = new Duration(
         microseconds: (rawTimeStamp.inMicroseconds / timeDilation).round());
     _haveScheduledVisualUpdate = false;
-    assert(_postFrameCallbacks.length == 0);
 
     Map<int, SchedulerCallback> callbacks = _transientCallbacks;
     _transientCallbacks = new Map<int, SchedulerCallback>();
@@ -68,9 +66,11 @@ class Scheduler {
     for (SchedulerCallback callback in _persistentCallbacks)
       invokeCallback(callback, timeStamp);
 
-    for (SchedulerCallback callback in _postFrameCallbacks)
-      invokeCallback(callback, timeStamp);
+    List<SchedulerCallback> localPostFrameCallbacks =
+        new List<SchedulerCallback>.from(_postFrameCallbacks);
     _postFrameCallbacks.clear();
+    for (SchedulerCallback callback in localPostFrameCallbacks)
+      invokeCallback(callback, timeStamp);
 
     _inFrame = false;
   }
@@ -133,13 +133,7 @@ class Scheduler {
   /// frame. In this case, the registration order is not preserved. Callbacks
   /// are called in an arbitrary order.
   void requestPostFrameCallback(SchedulerCallback callback) {
-    if (_inFrame) {
-      _postFrameCallbacks.add(callback);
-    } else {
-      _nextPrivateCallbackId -= 1;
-      _transientCallbacks[_nextPrivateCallbackId] = callback;
-      ensureVisualUpdate();
-    }
+    _postFrameCallbacks.add(callback);
   }
 
   /// Ensure that a frame will be produced after this function is called.
diff --git a/packages/flutter/lib/src/material/material_app.dart b/packages/flutter/lib/src/material/material_app.dart
index dc7bfb3f3a6..117c6d5c038 100644
--- a/packages/flutter/lib/src/material/material_app.dart
+++ b/packages/flutter/lib/src/material/material_app.dart
@@ -9,6 +9,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
 import 'package:flutter/src/widgets/navigator2.dart' as n2;
+import 'package:flutter/src/widgets/hero_controller.dart' as n2;
 
 import 'theme.dart';
 import 'title.dart';
@@ -86,12 +87,25 @@ class _MaterialAppState extends State<MaterialApp> {
 
   void _metricHandler(Size size) => setState(() { _size = size; });
 
+  final n2.HeroController _heroController = new n2.HeroController();
+
+  n2.Route _generateRoute(n2.NamedRouteSettings settings) {
+    return new n2.HeroPageRoute(
+      builder: (BuildContext context) {
+        RouteBuilder builder = config.routes[settings.name] ?? config.onGenerateRoute(settings.name);
+        return builder(new RouteArguments(context: context));
+      },
+      settings: settings,
+      heroController: _heroController
+    );
+  }
+
   Widget build(BuildContext context) {
     Widget navigator;
     if (_kUseNavigator2) {
       navigator = new n2.Navigator(
         key: _navigator,
-        routes: config.routes
+        onGenerateRoute: _generateRoute
       );
     } else {
       navigator = new Navigator(
diff --git a/packages/flutter/lib/src/widgets/hero_controller.dart b/packages/flutter/lib/src/widgets/hero_controller.dart
new file mode 100644
index 00000000000..3e0852bbce1
--- /dev/null
+++ b/packages/flutter/lib/src/widgets/hero_controller.dart
@@ -0,0 +1,112 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/animation.dart';
+import 'package:flutter/rendering.dart';
+
+import 'basic.dart';
+import 'framework.dart';
+import 'heroes.dart';
+import 'navigator2.dart';
+import 'overlay.dart';
+import 'page.dart';
+
+class HeroPageRoute extends PageRoute {
+  HeroPageRoute({
+    WidgetBuilder builder,
+    NamedRouteSettings settings: const NamedRouteSettings(),
+    this.heroController
+  }) : super(builder: builder, settings: settings);
+
+  final HeroController heroController;
+
+  void didMakeCurrent() {
+    heroController?.didMakeCurrent(this);
+  }
+}
+
+class HeroController {
+  HeroController() {
+    _party = new HeroParty(onQuestFinished: _handleQuestFinished);
+  }
+
+  HeroParty _party;
+  HeroPageRoute _from;
+  HeroPageRoute _to;
+
+  final List<OverlayEntry> _overlayEntries = new List<OverlayEntry>();
+
+  void didMakeCurrent(PageRoute current) {
+    assert(current != null);
+    assert(current.performance != null);
+    if (_from == null) {
+      _from = current;
+      return;
+    }
+    _to = current;
+    current.offstage = true;
+    scheduler.requestPostFrameCallback(_updateQuest);
+  }
+
+  void _handleQuestFinished() {
+    _removeHeroesFromOverlay();
+    _from = _to;
+    _to = null;
+  }
+
+  Rect _getAnimationArea(BuildContext context) {
+    RenderBox box = context.findRenderObject();
+    Point topLeft = box.localToGlobal(Point.origin);
+    Point bottomRight = box.localToGlobal(box.size.bottomRight(Point.origin));
+    return new Rect.fromLTRB(topLeft.x, topLeft.y, bottomRight.x, bottomRight.y);
+  }
+
+  void _removeHeroesFromOverlay() {
+    for (OverlayEntry entry in _overlayEntries)
+      entry.remove();
+    _overlayEntries.clear();
+  }
+
+  void _addHeroesToOverlay(Iterable<Widget> heroes, OverlayState overlay) {
+    OverlayEntry insertionPoint = _to.topEntry;
+    for (Widget hero in heroes) {
+      OverlayEntry entry = new OverlayEntry(child: hero);
+      overlay.insert(entry, above: insertionPoint);
+      _overlayEntries.add(entry);
+    }
+  }
+
+  Set<Key> _getMostValuableKeys() {
+    Set<Key> result = new Set<Key>();
+    if (_from.settings.mostValuableKeys != null)
+      result.addAll(_from.settings.mostValuableKeys);
+    if (_to.settings.mostValuableKeys != null)
+      result.addAll(_to.settings.mostValuableKeys);
+    return result;
+  }
+
+  void _updateQuest(Duration timeStamp) {
+    Set<Key> mostValuableKeys = _getMostValuableKeys();
+
+    Map<Object, HeroHandle> heroesFrom = _party.isEmpty ?
+        Hero.of(_from.pageKey.currentContext, mostValuableKeys) : _party.getHeroesToAnimate();
+
+    BuildContext context = _to.pageKey.currentContext;
+    Map<Object, HeroHandle> heroesTo = Hero.of(context, mostValuableKeys);
+    _to.offstage = false;
+
+    PerformanceView performance = _to.performance;
+    Curve curve = Curves.ease;
+    if (performance.status == PerformanceStatus.reverse) {
+      performance = new ReversePerformance(performance);
+      curve = new Interval(performance.progress, 1.0, curve: curve);
+    }
+
+    NavigatorState navigator = Navigator.of(context);
+    _party.animate(heroesFrom, heroesTo, _getAnimationArea(navigator.context), curve);
+    _removeHeroesFromOverlay();
+    Iterable<Widget> heroes = _party.getWidgets(navigator.context, performance);
+    _addHeroesToOverlay(heroes, navigator.overlay);
+  }
+}
diff --git a/packages/flutter/lib/src/widgets/heroes.dart b/packages/flutter/lib/src/widgets/heroes.dart
index 83f794d3b27..0dee9abd08a 100644
--- a/packages/flutter/lib/src/widgets/heroes.dart
+++ b/packages/flutter/lib/src/widgets/heroes.dart
@@ -387,11 +387,11 @@ class HeroParty {
           hero.targetState._setChild(hero.key);
         for (HeroState source in hero.sourceStates)
           source._resetChild();
-        if (onQuestFinished != null)
-          onQuestFinished();
       }
       _heroes.clear();
       _currentPerformance = null;
+      if (onQuestFinished != null)
+        onQuestFinished();
     }
   }
 
diff --git a/packages/flutter/lib/src/widgets/navigator2.dart b/packages/flutter/lib/src/widgets/navigator2.dart
index 6370862d496..354bb95cb5b 100644
--- a/packages/flutter/lib/src/widgets/navigator2.dart
+++ b/packages/flutter/lib/src/widgets/navigator2.dart
@@ -2,55 +2,56 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
-import 'package:flutter/animation.dart';
-
-import 'basic.dart';
 import 'framework.dart';
 import 'overlay.dart';
-import 'transitions.dart';
 
 abstract class Route {
-  /// Override this function to return the widget that this route should display.
-  Widget createWidget();
+  List<Widget> createWidgets() => const <Widget>[];
 
-  Widget _child;
-  OverlayEntry _entry;
+  OverlayEntry get topEntry => _entries.isNotEmpty ? _entries.last : null;
+  OverlayEntry get bottomEntry => _entries.isNotEmpty ? _entries.first : null;
 
-  void willPush() {
-    _child = createWidget();
+  final List<OverlayEntry> _entries = new List<OverlayEntry>();
+
+  void didPush(OverlayState overlay, OverlayEntry insertionPoint) {
+    List<Widget> widgets = createWidgets();
+    for (Widget widget in widgets) {
+      _entries.add(new OverlayEntry(child: widget));
+      overlay?.insert(_entries.last, above: insertionPoint);
+      insertionPoint = _entries.last;
+    }
   }
 
+  void didMakeCurrent() { }
+
   void didPop(dynamic result) {
-    _entry.remove();
+    for (OverlayEntry entry in _entries)
+      entry.remove();
   }
 }
 
-typedef Widget RouteBuilder(args);
-typedef RouteBuilder RouteGenerator(String name);
+class NamedRouteSettings {
+  const NamedRouteSettings({ this.name: '<anonymous>', this.mostValuableKeys });
 
-const String _kDefaultPageName = '/';
+  final String name;
+  final Set<Key> mostValuableKeys;
+}
+
+typedef Route RouteFactory(NamedRouteSettings settings);
 
 class Navigator extends StatefulComponent {
   Navigator({
     Key key,
-    this.routes,
-    this.onGeneratePage,
-    this.onUnknownPage
+    this.onGenerateRoute,
+    this.onUnknownRoute
   }) : super(key: key) {
-    // To use a navigator, you must at a minimum define the route with the name '/'.
-    assert(routes != null);
-    assert(routes.containsKey(_kDefaultPageName));
+    assert(onGenerateRoute != null);
   }
 
-  final Map<String, RouteBuilder> routes;
+  final RouteFactory onGenerateRoute;
+  final RouteFactory onUnknownRoute;
 
-  /// you need to implement this if you pushNamed() to names that might not be in routes.
-  final RouteGenerator onGeneratePage;
-
-  /// 404 generator. You only need to implement this if you have a way to navigate to arbitrary names.
-  final RouteBuilder onUnknownPage;
+  static const String defaultRouteName = '/';
 
   static NavigatorState of(BuildContext context) {
     NavigatorState result;
@@ -68,139 +69,74 @@ class Navigator extends StatefulComponent {
 }
 
 class NavigatorState extends State<Navigator> {
-  GlobalKey<OverlayState> _overlay = new GlobalKey<OverlayState>();
-  List<Route> _history = new List<Route>();
+  final GlobalKey<OverlayState> _overlayKey = new GlobalKey<OverlayState>();
+  final List<Route> _ephemeral = new List<Route>();
+  final List<Route> _modal = new List<Route>();
 
   void initState() {
     super.initState();
-    _addRouteToHistory(new PageRoute(
-      builder: config.routes[_kDefaultPageName],
-      name: _kDefaultPageName
-    ));
+    push(config.onGenerateRoute(new NamedRouteSettings(name: Navigator.defaultRouteName)));
   }
 
-  RouteBuilder _generatePage(String name) {
-    assert(config.onGeneratePage != null);
-    return config.onGeneratePage(name);
+  bool get hasPreviousRoute => _modal.length > 1;
+  OverlayState get overlay => _overlayKey.currentState;
+
+  OverlayEntry get _currentOverlay {
+    for (Route route in _ephemeral.reversed) {
+      if (route.topEntry != null)
+        return route.topEntry;
+    }
+    for (Route route in _modal.reversed) {
+      if (route.topEntry != null)
+        return route.topEntry;
+    }
+    return null;
   }
 
-  bool get hasPreviousRoute => _history.length > 1;
+  Route get _currentRoute => _ephemeral.isNotEmpty ? _ephemeral.last : _modal.last;
+
+  Route _removeCurrentRoute() {
+    return _ephemeral.isNotEmpty ? _ephemeral.removeLast() : _modal.removeLast();
+  }
 
   void pushNamed(String name, { Set<Key> mostValuableKeys }) {
-    final RouteBuilder builder = config.routes[name] ?? _generatePage(name) ?? config.onUnknownPage;
-    assert(builder != null); // 404 getting your 404!
-    push(new PageRoute(
-      builder: builder,
+    NamedRouteSettings settings = new NamedRouteSettings(
       name: name,
       mostValuableKeys: mostValuableKeys
-    ));
-  }
-
-  void _addRouteToHistory(Route route) {
-    route.willPush();
-    route._entry = new OverlayEntry(child: route._child);
-    _history.add(route);
+    );
+    push(config.onGenerateRoute(settings) ?? config.onUnknownRoute(settings));
   }
 
   void push(Route route) {
-    OverlayEntry reference = _history.last._entry;
-    _addRouteToHistory(route);
-    _overlay.currentState.insert(route._entry, above: reference);
+    _popAllEphemeralRoutes();
+    route.didPush(overlay, _currentOverlay);
+    _modal.add(route);
+    route.didMakeCurrent();
+  }
+
+  void pushEphemeral(Route route) {
+    route.didPush(overlay, _currentOverlay);
+    _ephemeral.add(route);
+    route.didMakeCurrent();
+  }
+
+  void _popAllEphemeralRoutes() {
+    List<Route> localEphemeral = new List<Route>.from(_ephemeral);
+    _ephemeral.clear();
+    for (Route route in localEphemeral)
+      route.didPop(null);
+    assert(_ephemeral.isEmpty);
   }
 
   void pop([dynamic result]) {
-    _history.removeLast().didPop(result);
+    _removeCurrentRoute().didPop(result);
+    _currentRoute.didMakeCurrent();
   }
 
   Widget build(BuildContext context) {
     return new Overlay(
-      key: _overlay,
-      initialEntries: <OverlayEntry>[ _history.first._entry ]
+      key: _overlayKey,
+      initialEntries: _modal.first._entries
     );
   }
 }
-
-abstract class TransitionRoute extends Route {
-  PerformanceView get performance => _performance?.view;
-  Performance _performance;
-
-  Duration get transitionDuration;
-
-  Performance createPerformance() {
-    Duration duration = transitionDuration;
-    assert(duration != null && duration >= Duration.ZERO);
-    return new Performance(duration: duration, debugLabel: debugLabel);
-  }
-
-  void willPush() {
-    _performance = createPerformance();
-    _performance.forward();
-    super.willPush();
-  }
-
-  Future didPop(dynamic result) async {
-    await _performance.reverse();
-    super.didPop(result);
-  }
-
-  String get debugLabel => '$runtimeType';
-  String toString() => '$runtimeType(performance: $_performance)';
-}
-
-class _Page extends StatefulComponent {
-  _Page({ Key key, this.route }) : super(key: key);
-
-  final PageRoute route;
-
-  _PageState createState() => new _PageState();
-}
-
-class _PageState extends State<_Page> {
-  final AnimatedValue<Point> _position =
-      new AnimatedValue<Point>(const Point(0.0, 75.0), end: Point.origin, curve: Curves.easeOut);
-
-  final AnimatedValue<double> _opacity =
-      new AnimatedValue<double>(0.0, end: 1.0, curve: Curves.easeOut);
-
-  Widget build(BuildContext context) {
-    return new SlideTransition(
-      performance: config.route.performance,
-      position: _position,
-      child: new FadeTransition(
-        performance: config.route.performance,
-        opacity: _opacity,
-        child: _invokeBuilder()
-      )
-    );
-  }
-
-  Widget _invokeBuilder() {
-    Widget result = config.route.builder(null);
-    assert(() {
-      if (result == null)
-        debugPrint('The builder for route \'${config.route.name}\' returned null. Route builders must never return null.');
-      assert(result != null && 'A route builder returned null. See the previous log message for details.' is String);
-      return true;
-    });
-    return result;
-  }
-}
-
-class PageRoute extends TransitionRoute {
-  PageRoute({
-    this.builder,
-    this.name: '<anonymous>',
-    this.mostValuableKeys
-  }) {
-    assert(builder != null);
-  }
-
-  final RouteBuilder builder;
-  final String name;
-  final Set<Key> mostValuableKeys;
-
-  Duration get transitionDuration => const Duration(milliseconds: 150);
-  Widget createWidget() => new _Page(route: this);
-
-  String get debugLabel => '${super.debugLabel}($name)';
-}
diff --git a/packages/flutter/lib/src/widgets/overlay.dart b/packages/flutter/lib/src/widgets/overlay.dart
index 8e8ec6f570f..fc289fbb397 100644
--- a/packages/flutter/lib/src/widgets/overlay.dart
+++ b/packages/flutter/lib/src/widgets/overlay.dart
@@ -16,6 +16,8 @@ class OverlayEntry {
   bool get opaque => _opaque;
   bool _opaque;
   void set opaque(bool value) {
+    if (_opaque = value)
+      return;
     _opaque = value;
     _state?.setState(() {});
   }
@@ -51,10 +53,6 @@ class OverlayState extends State<Overlay> {
 
   void insert(OverlayEntry entry, { OverlayEntry above }) {
     assert(entry._state == null);
-    if (above != null) {
-      print('above._state ${above._state} --- ${above._state == this}');
-      print('_entries.contains ${_entries.contains(above)}');
-    }
     assert(above == null || (above._state == this && _entries.contains(above)));
     entry._state = this;
     setState(() {
diff --git a/packages/flutter/lib/src/widgets/page.dart b/packages/flutter/lib/src/widgets/page.dart
new file mode 100644
index 00000000000..4e1341a886a
--- /dev/null
+++ b/packages/flutter/lib/src/widgets/page.dart
@@ -0,0 +1,145 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/animation.dart';
+
+import 'basic.dart';
+import 'framework.dart';
+import 'navigator2.dart';
+import 'overlay.dart';
+import 'transitions.dart';
+
+// TODO(abarth): Should we add a type for the result?
+abstract class TransitionRoute extends Route {
+  bool get opaque => true;
+
+  PerformanceView get performance => _performance?.view;
+  Performance _performance;
+
+  Duration get transitionDuration;
+
+  Performance createPerformance() {
+    Duration duration = transitionDuration;
+    assert(duration != null && duration >= Duration.ZERO);
+    return new Performance(duration: duration, debugLabel: debugLabel);
+  }
+
+  dynamic _result;
+
+  void _handleStatusChanged(PerformanceStatus status) {
+    switch (status) {
+      case PerformanceStatus.completed:
+        bottomEntry.opaque = opaque;
+        break;
+      case PerformanceStatus.forward:
+      case PerformanceStatus.reverse:
+        bottomEntry.opaque = false;
+        break;
+      case PerformanceStatus.dismissed:
+        super.didPop(_result);
+        break;
+    }
+  }
+
+  void didPush(OverlayState overlay, OverlayEntry insertionPoint) {
+    _performance = createPerformance()
+      ..addStatusListener(_handleStatusChanged)
+      ..forward();
+    super.didPush(overlay, insertionPoint);
+  }
+
+  void didPop(dynamic result) {
+    _result = result;
+    _performance.reverse();
+  }
+
+  String get debugLabel => '$runtimeType';
+  String toString() => '$runtimeType(performance: $_performance)';
+}
+
+class _Page extends StatefulComponent {
+  _Page({
+    Key key,
+    this.route
+  }) : super(key: key);
+
+  final PageRoute route;
+
+  _PageState createState() => new _PageState();
+}
+
+class _PageState extends State<_Page> {
+  final AnimatedValue<Point> _position =
+      new AnimatedValue<Point>(const Point(0.0, 75.0), end: Point.origin, curve: Curves.easeOut);
+
+  final AnimatedValue<double> _opacity =
+      new AnimatedValue<double>(0.0, end: 1.0, curve: Curves.easeOut);
+
+  final GlobalKey _subtreeKey = new GlobalKey();
+
+  Widget build(BuildContext context) {
+    if (config.route._offstage) {
+      return new OffStage(
+        child: new KeyedSubtree(
+          key: _subtreeKey,
+          child: _invokeBuilder()
+        )
+      );
+    }
+    return new SlideTransition(
+      performance: config.route.performance,
+      position: _position,
+      child: new FadeTransition(
+        performance: config.route.performance,
+        opacity: _opacity,
+        child: new KeyedSubtree(
+          key: _subtreeKey,
+          child: _invokeBuilder()
+        )
+      )
+    );
+  }
+
+  Widget _invokeBuilder() {
+    Widget result = config.route.builder(context);
+    assert(() {
+      if (result == null)
+        debugPrint('The builder for route \'${config.route.name}\' returned null. Route builders must never return null.');
+      assert(result != null && 'A route builder returned null. See the previous log message for details.' is String);
+      return true;
+    });
+    return result;
+  }
+}
+
+class PageRoute extends TransitionRoute {
+  PageRoute({
+    this.builder,
+    this.settings: const NamedRouteSettings()
+  }) {
+    assert(builder != null);
+    assert(opaque);
+  }
+
+  final WidgetBuilder builder;
+  final NamedRouteSettings settings;
+
+  final GlobalKey<_PageState> pageKey = new GlobalKey<_PageState>();
+
+  String get name => settings.name;
+
+  Duration get transitionDuration => const Duration(milliseconds: 150);
+  List<Widget> createWidgets() => [ new _Page(key: pageKey, route: this) ];
+
+  bool get offstage => _offstage;
+  bool _offstage = false;
+  void set offstage (bool value) {
+    if (_offstage == value)
+      return;
+    _offstage = value;
+    pageKey.currentState?.setState(() { });
+  }
+
+  String get debugLabel => '${super.debugLabel}($name)';
+}